Cam-acting tension device for frameless window screens



Jan. 20, 1953 D. J. RUST ETAL 2,625,995

CAM-ACTING TENSION DEVICE FOR FRAMELESS WINDOW SCREENS Filed April 301951 2 SHEETSSHEET l mvr-znrons David J: Rusi JackJiJensen BY MIT Jan.20, 1953 D. J. RUST ET AL 2,625,995

CAM-ACTING TENSION DEVICE FOR FRAMELESS WINDOW SCREENS Filed April 50,1951 2 Sl-lEETS-SHEET 2 Fig.2

z 13 15 El? 1 l6 14 paw-A5222" Jack J.Jensen BY Mil ATTORII EYS PatentedJan. 20, 1953 CAM-ACTING TENSION David Jordan Rust and Leandro, Califl,assignors DEVICE FOR FRAMELESS WINDOW SCREENS Jack H. Jensen, San toRy-Lock Company,

Ltd., San Leandro, Calif., a corporation of California 2 Claims.

This invention pertains generally to improvements in frameless windowscreens.

In particular the invention relates to, and it is an object to provide,a novel device for tensioning a frameless window screen.

Such tensioning device includes an initially upstanding cam leverpivotally mounted in connection with the window frame for downwardswinging motion in a lateral direction; the cam of such lever being atits lower end portion and engaging in a channel fixed on the bottomcross bar of the screen, and said cam acting to forcefully lower thebottom cross bar and to thus tension the screen upon the cam lever beingso swung.

As the cam has a rotary motion when the cam lever is swung between anupstanding released position and a lowered screen tensioning position,with such motion in a laterally outward direction at the lower, channelengaging edge, there is a tendency for said cam to undesirably shift thechannel and attached bottom cross bar in a corresponding lateraldirection with possible improper positioning of the screen under tensionin the window opening.

It is therefore an important object of the invention to provide a novelcam and channel assembly which is operative to impart the desiredtension to the screen, but also acts in a manner to prevent outwardlateral displacement of the channel and bottom cross bar by rotarymotion of the channel engaging cam.

Another object of the invention is to provide a tensioning device, as inthe preceding paragraph, wherein the tendency of the channel and bottomcross bar to displace laterally in an outward direction is counteractedby inclining the channel upwardly in the opposite direction.

It is also an object of the invention to provide a cam-acting tensiondevice for frameless window screens which is designed for ease andeconomy of manufacture.

Still another object of the invention is to provide a practical andreliable tensioning device for irameless window screens, and one whichwill be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relativearrangement of parts as will fully appear by a perusal oi the followingspecification and claims.

In the drawings:

Fig. 1 is a fragmentary rear elevation of a frameless window screenshowing a pair of the tensioning devices as used in connectiontherewith; the cam lever of the right-hand device be ing in itsupstanding released position, while the cam lever of the left-handdevice is in its lowered screen tensioning position.

Fig. 2 is a cross section on line 2-2 of Fig. l, but with the cam leverraised.

Fig. 3 isa cross section on line 3-3 of Fig. 1.

Referring now more particularly to the characters of reference on thedrawings, the frameless window screen is here shown as disposed in awindow frame, indicated generally at l, which frame includes, atopposite sides 2, the usual vertical blind stops it. The sill isindicated at i.

The irameless window screen is of the type which includes a section ofwire cloth 5 fitted with a bottom cross bar 6 and a top cross bar (notshown) the latter being secured to the header of the window frame I bysuitable means.

The bottom cross bar 6 includes a vertically adjustable U-shaped bottomstrip 1 whose purpose is to provide a full closure between the bottomcross bar 5 and the top of the sill G.

The section of Wire cloth 5 is normally maintained under tension or tautby means of tensioning devices, indicated generally at 8; there being apair of said devices, each working between one of the blind stops 3 andthe corresponding end portion of the bottom cross bar 5.

As the tensioning devices 8 are of identical construction, except forbeing right and left hand, a description of one will sufiice for both.

Each tensioning device 8 comprises an elongated mounting strip 9 securedin fixed relation to the back side of the bottom cross bar 6 above thebottom strip 1; such mounting strip 9 including, in integral relation,an upwardly opening catch channel It which is disposed closely adjacent,but terminates short of, the correspond ing end of the bottom cross bar6, whereby said catch channel does not engage the related blind stop 3.

The catch channel H3 is disposed at an upward incline from its laterallyoutermost end; the purpose of this inclination being hereinafterdescribed.

An integral deflector tongue H extends at an outward and downwardincline from the rear upper edge of the catch channel it, while a fingerpull I2 projects rearwardly and upwardly from the mounting strip 9laterally inwardly of said catch channel Iii.

A bracket unit, indicated generally at I3, and which is described indetail in my copending application, Serial No. 223,763, filed April 30,1951, is secured to the adjacent side of the corresponding blind stop 3directly beyond but mainly above the catch channel I 0; said bracketunit including a vertically adjustable attachment plate I 4 affixed tothe blind stop 3 by a headed screw I5 which works through a verticalslot I6 in said plate I4,

An integral bracket plate I1 projects at a rightangle to the attachmentplate I4 in a horizontal, laterally inward direction, and serves as themount for a flat cam lever, indicated at I8.

At its lower end pivoted, as at I 9, in face to face engagementwith thebracket plate IT, for swinging between. an

upstanding released position, asatl the right in,

Fig. 1, and a lowered screen tensioningposition as at the left in suchfigure. At the end portion opposite the pivot I9 the cam lever Itincludes a finger tab 20 to facilitate manipulation of said lever.

The pivoted lower end portion of the lever I8 forms. an eccentric rotaryc am, indicatedv at 2;I; this being accomplished by making the distancebetween the pivot I9 andthe rounded or arcuate initially lower edge 22of theleven less than the distance between such pivot and the. initiallylaterally inner straight edge 23. ofthe lever I8.

Thus, when the lever I 8'is swung downward from its upstanding positionto a substantially horizontal position, the cam 2|, Working in the catchchannel I .ILurges the latter-together with the bottom cross bar6-downwardly, forcefully efiectively tensioning the screen. In. itslowered, screen tensioning positionythe lever I8 passes dead-centerwithrespect, to the cam shape-and and is thus. in efiect rleasably latched.

Upon the cam lever I8 being swung from its upstandingreleasedposition toits lowered screen tensionin -position, the cam 2I turns in alaterallyoutward directionat the bottom; i. e. below the pivot IS. Theresult ista tendency of the partturning or. rotating cam toshift thecatch channel I0 and the bottoms cross bar 6 likewise in a laterallyoutward direction; there normally being some end play between the bottomcross bar 6 and opposite sides of the window frame I. It is undesirablethat such displacement of the bottom cross bar 6, occur, asthismisalines the screen in thewindow frame I and prevents propertensioning thereon by the transversely spaced tensioning devices 8.

It isjtherefore necessary that such tendency of ottomv cross ba 8 odisplac n a l ally outward direction be counteracted, and this isaccomplished by incliningeach catch channel It in the manner heretoforedescribed. With the catch channel ID inclined upwardly in a lateral- 1y.inwa directi n. opposed, fo ce i od ce when the cam. His part-rotated,which force counter actsfthe, tendency of the cross bar 6 to sp ac i a da ra ly ut r g n: T e expedient employed for the purpose is simple,

7 but nevertheless is most effective to accomplish thedesired end;to-wit, the maintenance of the frameless window screen in properalinement in the window frame I when the tensioning devices 8 aremanipulated to their screen tensioning positions, V

The finger pull [2 is used to initially draw the portion the camlever I8isv 4 bottom cross bar 6 against the blind stops 3, whence the lower orcam end of the lever I8 engages the deflector tongue II and easilysnapengages in catch channel I0.

From the foregoing description it will be readily seen that there hasbeen. produced such a device as substantially fulfillsthe objects of?the invention, as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of the device, still in .practicesuch deviations therefrommay be resorted toas do not form a departure from the spirit of theinvention, as defined by the appended V Havingthus described theinvention, the following is claimed; as new and useful, and upon whichLetters Batent are desired:

1'. In a tensioning device for a frameless window screen having a bottomcross bar extending between opposite sides of a window frame; a camlever. pivoted inconnee on with the window frame at one side thereof-anbar, the cam lever b 'ng' swingable downwardly from an upstandir' g,rvraised position inia direction parallel to the screenand to a loweredscreen tensioning position, an upwardlyfacing element fixed on thebottom cross bar belowthe lever; the

lower end ortion of the lever being a rotary cam abutting said element,said cam, turning at the bottom edge in I a laterally; outward directionand simultaneously thrusting downwardly upon swinging of the lever, andsaid element being inclined upwardly in arropposite direction whereby tocounteract the tendency of the turning cam to displace said element andthe cross bar in said laterally outward direction.

2. In a tensioning device for a frameless window screenhaving. a.bottom, cross bar extending between Opposite sides era window frame; acam lever pivotedin connection with thewindow frame at one side thereofand adjacent the bottom. cross bar, the cam lever being swingabledownwardly fromanupstanding released position to a loweredscreentensioning position in a direction parallel to the screen, and, anupwardly opening longitudinal, channel, fixed on the bottom cross barbelow thevlev'en the lower end, portion of the lever being a rotary camengaged in the channel, said cam turning at the bottom edge in alaterally outward direction and simultaneously thrusting downwardly uponswinging of the lever, and said channel being inclined upwardly in anopposite direction whereby to counteract the tendency of the turning camto displace the said channel and the cross bar in said laterally outwarddirection.

DAVID JORDAN RUST.

JACK H'. JENSEN.

' REFERENCES cIrE The following references are of record in the file ofthis patent:

UNITED STATES, PATENTS Number Name Date 876,822 Maxwell Jan. 14, 19082,021,068 Kammerer Nov. 12, 1935 2,146,251 Dominick Feb. 7, 1939 dadjacent the b'o omvqr s.

